SATA RAID Level 4?
Anybody seen any SATA RAID cards that do level 4?
I want parity but only have room for 3 drives, so RAID 1+0 is out of the question. Furthermore I don't want the read overhead that RAID 5 brings unless I have no option.
PCI, PCI 64bit, or PCI Express are all in the equation.
Cheers,
Kez.
PHP Code:$s = new signature();
$s->sarcasm()->intellect()->font('Courier New')->display();
Raid 4 huh - an unusual choice.
Degradation and Rebuilding
Moderate degrading if a drive fails; potentially lengthy rebuilds.
Random Read Performance
Very good
Random Write Performance
Poor to fair, due to parity calculation overhead and the bottleneck of the dedicated parity drive.
Sequential Read Performance
Good to very good.
Sequential Write Performance
Fair to good.
Recommended Uses
Jack of all trades and master of none, RAID 4 is not as commonly used as RAID 3 and RAID 5, because it is in some ways a "compromise" between them that doesn't have a target market as well defined as either of those two levels.
Good luck finding a SATA raid controller that supports Raid 4 - i dont think you will find one to be honest its so little used.
Butuz
You'd be better off with Raid 5 That gives the ideal combination of good performance good fault tolerance and high capacity. Plus raid 5 SATA controllers are readily available to you.
Butuz
Well I guess, the only trouble is read speeds are better on 4 than 5.
OK then, time to pose a new question: A RAID card with an onboard processor for XOR calculations...?
PHP Code:$s = new signature();
$s->sarcasm()->intellect()->font('Courier New')->display();
http://www.promise.com/product/produ...112&familyId=2
Oh OK I've found it!
Looks like £150 to £200 - so I dare you all to find me a cheaper card, lol.
Cheers,
Kez.
PHP Code:$s = new signature();
$s->sarcasm()->intellect()->font('Courier New')->display();
Nope, this is a software controller, and doesn't use a CPU of its own. If you want a card w/dedicated CPU to handle this w/out impacting CPU performance, try http://www.adaptec.com/worldwide/sup...&fromarea=prodPromise's FastTrak S150 SX4 controller uses an integrated XOR engine for parity calculations, delivering extraordinary performance at a dramatically lower price. This approach takes advantage of today's ultra-powerful PC CPUs to manage the array and outperform traditional RAID 5 solutions.
That's microprocessor driven.#
edit: Or http://www.3ware.com/products/serial_ata.asp
Last edited by nichomach; 12-05-2004 at 02:17 PM.
Looks like a bit of a halfway house- tbh - it's not completely software, but not completely hardware - to quote the first googled review:
http://www.somacon.com/fasttrak_sx4/page10.php
The XOR parity calculations and the RAID-5 distribution algorithms require a significant amount of processing power, even assuming modern processors. Traditional RAID-5 controllers contain an expensive, embedded processor to handle these calculations. The FastTrak S150 SX4, on the other hand, runs the RAID-5 algorithms on the main CPU and runs the profuse but simpler XOR parity calculations using a less expensive chip on the controller.
Love the way they added hdds for this review:
http://www.somacon.com/fasttrak_sx4/page20.php
Now go away before I taunt you a second time.
Use the 3ware SATA controllers. They rock - and perform well.
KEZ read speeds (especially sequential reads) are superb on raid 5 its only write speeds that are slower. On raid 5 the read speed increases for every drive you add, 3 drives in raid 5 will give a faster read speed than either 3 drives in raid 4 or 2 drives in raid 0 as there are 3 drives with which data can be taken from at the same time wheras with raid 4 one drive is used soly for parity leaving only 2 drives for reading from. In my experience with SCSI raid 5 over 6 disks - its fast as burglery and you should be well pleased.
Don't forget if your going raid 5 for security then hot swap drive bays are a huge bonus, you may not have downtime coz of a drive failing but if you have to unplug the PC in order to screwdriver out a failed HDD and then screwdriver in a new one - thats not particularly good.
Butuz
Last edited by Butuz; 12-05-2004 at 03:01 PM.
Thanks guys.
This isn't for a server - just the rig I'll be taking to Uni in a years time. The way I see it, I have two 80Gig 'cuda's and I can get another one and stick it in RAID 5. I can't make it hotswappable unfortunately, as the LCD mod will be in the way and the 5.25" bays will be used for watercooling/neon control/DVD burner.
The main purpose is to take the piss and have bragging rights.
edit: The 3ware ones look damn nice, but a bit steep in price for the purpose I seek. I reckon thus far the Promise card has the most... well... promise, lol.
Last edited by Steve; 12-05-2004 at 03:34 PM.
PHP Code:$s = new signature();
$s->sarcasm()->intellect()->font('Courier New')->display();
OT, but which uni you off to mate ?
Originally Posted by Saracen
Well hopefully it'll be bristol - they do a nice MsC in Computer Systems Engineering with study abroad. Not applying until next Semester though (2005 entry).
PHP Code:$s = new signature();
$s->sarcasm()->intellect()->font('Courier New')->display();
There are currently 1 users browsing this thread. (0 members and 1 guests)
SCAN.care@HEXUS
Posting Permissions
LinkBack URL
About LinkBacks
Reply With Quote